This invention relates to a new process for the preparation of garamine and garamine derivatives. In particular, it relates to a process for preparing garamine and garamine derivatives whose amino and/or hydroxyl groups are completely or partially protected.
Garamine has hitherto only been preparable by partial hydrolysis of sisomycin. The unsaturated 2,6-diaminosugar unit of sisomycin is split off relatively easily, whereupon the garamine unit is obtained. Generally, penta-N-carbobenzoxy-sisomycin is employed for the hydrolysis. On the other hand, it has been held by the prior art (e.g., J. C. S. Perkin 1976, page 1,088) that garamine cannot be prepared from the clinically important gentamycins C.sub.1, C.sub.2 and C.sub.1a (or from the naturally occurring gentamycin complex, which is a mixture of these substances), since, as a result of the presence of a 2'-amino group, the glycoside bonds of the purpurosamine unit are more stable towards acid hydrolysis.